ZAG is a soluble glyprotein with molecular weight of 42kD, which was first isolated and purified from human serum by Burgi et al. in 196112. ZAG is widely found in human body fluids, with carrier protein, ribonuclease activity and other functions9. In recent years, many studies have shown that ZAG has function of regulating immunity, cell adhesion, and regulating of melanin production13,14. Some studies15–17 also pointed out that ZAG can be used as a biomarker for the early diagnosis of cancer, and its can participate in regulating tumor cell proliferation and glucose metabolism18. In addition, in vivo and in vitro experiments confirmed that ZAG can promote fat mobilization, suggesting that ZAG is involved in fat catabolism19,20. At present, most studies on ZAG are limited to type 2 diabetes, but its relationship with GDM is seldom studied.
According to the study, we found that the serum ZAG level of GDM patients was lower than that of the control group, and regression analysis showed that the serum ZAG level of GDM patients was related to FINS, HOMA-IR and HDL. The analysis suggested that ZAG may play a certain role in the metabolism of serum glucose and lipid in GDM patients, and it has some positive significance in reducing insulin resistance in GDM patients. Yang M et al.18 also showed that ZAG was related to insulin resistance, which was consistent with this study. Naf S et al.6 also pointed out that serum ZAG level in GDM patients was related to HDL, suggesting that ZAG was involved in lipid metabolism in GDM patients. However, no statistic difference was found between the GDM group and the NGT group in serum ZAG level, which may be caused by factors such as different races, research methods and sample size. In addition, Naf S et al. measured the serum ZAG level before delivery, while our study collected the detection indicators of pregnant women with GDM at 24 to 28 weeks, which may lead to the difference between the two studies.
In summary, the serum ZAG level of GDM patients was lower than that of the control group, and the changes were related to FINS, HOMA-IR and HDL. Serum ZAG level may be a new predictor of lipid metabolism and insulin resistance in patients with GDM, and may provide a potential therapeutic target for improving serum lipid disorder and insulin resistance in GDM patients. However, the sample size of our study was relatively small. Currently, there are few studies on the relationship between serum ZAG and GDM, and more evidence-based medical evidence is still needed. Therefore, it is still necessary to carry out multi-center and multi-area large sample study in the future to further clarify the relationship between serum ZAG and GDM.